Since the 1990s, there has been a reduction in the homicide rate in Denmark and other Western countries. Our hypothesis is that part of the decrease in the sharp force homicide rate can be explained by better and faster medical treatment over time, and we explore this via stab wound homicides, the largest group of homicides in Denmark. To investigate our hypothesis we undertook an epidemiological study of 428 stab wound homicides in Denmark 1992–2016 based on autopsy reports with registration of stab wounds, quantification of injury severity, treatment intensity and survival time. During 1992–2016, there was a significant reduction in the annual number of victims with a single stab wound, but no reduction in victims with multiple stab wounds. Victims with single stab wounds reached the hospital more often, survived longer and had less severe injuries (New Injury Severity Score (NISS)) than victims with multiple stab wounds. Higher NISS correlated with shorter survival time for all the stab wound victims and for the subgroup that underwent medical treatment. During the 25-year study period, the proportion of victims who underwent surgery before dying increased threefold. The victims in the first half of the study period had shorter survival times than the victims in the last half. We concluded that better and faster medical treatment could partly be responsible for the observed decrease in the number of single stab wound homicides and thereby possibly also in the total number of stab wound homicides.